Validity issues

The quality of information these instruments obtain is clearly of central importance. We know that they do not obtain the same information as each other, nor do they identify the same persons as cases of a particular diagnostic category. Their validity is therefore a matter of considerable concern for administrators using the data obtained in large surveys to guide planning. But it is also a matter of concern for aetiological research. A general tendency is for the lay interviews to obtain higher case rates than an instrument such as SCAN. An important study by Brugha et al.(47> compared SCAN, CIS-R, and CIDI on a sample of the general population, finding that agreement was generally poor, with kappa values between 0.1 and 0.4. Their recommendation is that SCAN now be assessed for its performance when it is in the hands of thoroughly trained lay interviewers. Meanwhile, it is not possible to say which of the available instruments is superior. Further technical developments are urgently needed in this demanding area.

Autism is a developmental disorder that manifests itself in early childhood and affects the functioning of the brain, primarily in the areas of social interaction and communication. Children with autism look like other children but do not play or behave like other children. They must struggle daily to cope and connect with the world around them.